diff --git a/pecan/routing.py b/pecan/routing.py
index aed8ad5..9b2f57b 100644
--- a/pecan/routing.py
+++ b/pecan/routing.py
@@ -1,3 +1,4 @@
+import logging
 import re
 import warnings
 from inspect import getmembers, ismethod
@@ -12,6 +13,8 @@ __all__ = ['lookup_controller', 'find_object', 'route']
 __observed_controllers__ = set()
 __custom_routes__ = {}
 
+logger = logging.getLogger(__name__)
+
 
 def route(*args):
     """
@@ -170,18 +173,16 @@ def lookup_controller(obj, remainder, request=None):
 def handle_lookup_traversal(obj, args):
     try:
         result = obj(*args)
+    except TypeError as te:
+        logger.debug('Got exception calling lookup(): %s (%s)',
+                     te, te.args)
+    else:
         if result:
             prev_obj = obj
             obj, remainder = result
             # crossing controller boundary
             cross_boundary(prev_obj, obj)
             return result
-    except TypeError as te:
-        msg = 'Got exception calling lookup(): %s (%s)'
-        warnings.warn(
-            msg % (te, te.args),
-            RuntimeWarning
-        )
 
 
 def find_object(obj, remainder, notfound_handlers, request):
diff --git a/pecan/tests/test_base.py b/pecan/tests/test_base.py
index 20a337b..0969755 100644
--- a/pecan/tests/test_base.py
+++ b/pecan/tests/test_base.py
@@ -339,11 +339,20 @@ class TestLookups(PecanTestCase):
             def _lookup(self, someID):
                 return 'Bad arg spec'  # pragma: nocover
 
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore")
-            app = TestApp(Pecan(RootController()))
-            r = app.get('/foo/bar', expect_errors=True)
-            assert r.status_int == 404
+        app = TestApp(Pecan(RootController()))
+        r = app.get('/foo/bar', expect_errors=True)
+        assert r.status_int == 404
+
+    def test_lookup_with_wrong_return(self):
+        class RootController(object):
+            @expose()
+            def _lookup(self, someID, *remainder):
+                return 1
+
+        app = TestApp(Pecan(RootController()))
+        self.assertRaises(TypeError,
+                          app.get,
+                          '/foo/bar', expect_errors=True)
 
 
 class TestCanonicalLookups(PecanTestCase):